Under normal conditions enough of the bacteria survive to make life miserable for millions of teenagers.

But US researchers have identified an active protein in the virus that could be developed as a new acne treatment.

“Acne affects millions of people, yet we have few treatments that are both safe and effective,” said lead scientist Professor Robert Modlin, from the University of California at Los Angeles (UCLA).

“Harnessing a virus that naturally preys on the bacteria that causes pimples could offer a new tool against the physical and emotional scars of severe acne.”

Sex hormones, oily skin and the immune system all play a role in acne, but a key cause of the condition is the skin bug Propionbacterium acnes. When the bacteria multiply they aggravate the immune system, triggering swollen red bumps.